Arrangement to produce electrical signals in belt conveyors using containers



April 18, 1961 Filed Aug. 1, 1957 F. MITTAG ETAL ARRANGEMENT TO PRODUCEELECTRICAL. SIGNALS IN BELT CONVEYORS USING CONTAINERS 2 Sheets-Sheet lRe/I Relfl Fig. 7

I: Ml'i'i'a Jill miner BY M ATTORNEY INVENTOR April 18, 1961 F I MITTAGETAL 2,930,235

ARRANGEMENT TO PRODUCE ELECTRICAL SIGNALS IN BELT CONVEYORS USINGCONTAINERS Filed Aug. 1, 1957 2 Sheets-Sheet 2 1 INVENTOR ATTORNEY2,980,235; ARRANGEMENT T PRODUCE ELECTRICAL.

T SIGNALS IN BELT CONVEYORS. USING CONTAINERS Fritz Mittag,Berlin-Friedman, 'and Jiirgen Lindner, Berlin, Germany, assignors toInternational Standard Electric Corporation, New York, N.Y., acorporation ofDelaware Filed Aug. 1, 1951, Ser. No.67 5,722 4 Claims.I(Cl.19838) This invention relates to electrical signalling, and, moreparticularly, to an arrangement for deriving electrical signals in aconveyor system by changing the impedance of an inductive circuit. e

It is known in the prior art to'produce electrical signals by means ofpermanent magnets being brought into proximity with saturable reactors,the mode of operation being such that the permanent magnet may aid inthe saturation of the iron, core of the reactor andthereby decrease itsimpedance to the fiow of alternating current applied to one of itswindings; The prior art teaches the use of pre-rnagnetizing windings forsuch reactors but the flux developed by said pro-magnetizing windings isinsufiicient to decrease the AC. impedance of the reactor unless aidedby the permanent magnet. It will be understood that the magnet must bepoled in aiding relation 2,980,235 Patented Apr. 18, 1961 Fig. 3 is aview of a magnet with switching indicia imprinted thereon, Referring nowto Fig. 1 there is shown schematically a cross-section of aconveyor-belt B which should be assumed to be moving at right angles tothe plane of the sheet of the drawing. Carried by the belt B is anarticle container for box K having a suitable shape for carryingarticles. The shape of the box K is more clearly shown in Fig. 2. Itmust be understood, however, that the shape of the box chosen for theillustration is non-limitative and any suitable shape may be utilized.As will be seen from Figs. 1 and 2, there is rotatably attached to onewall of the box-a pair of permanent magnets M1 and M2. These magnets arepivotally mounted on fixed pivot D which extends into the wall of thebox K. In Fig. 1, these magnets are shown with indicia on one facethereof, and in Fig. 2, they are shown with indicia on the ends thereof.It will be observed from Fig. 1 that when magnet M1 is in the positionwherein the numbers 2 and 4 are in the vertical plane, the North pole ofthe magnet will face the bottom of the container K and the South polewill face the upper portion of the container. Below the belt B there issituated a pair of saturable reactors J1, J2 having pre-magnetizationwindings W1, W2 energized by an appropriate source of direct currentindicated by'batteries BA1 and BA2, respectively. The

to the flux in the core developed by the pre-magnetizing winding, andthat if the magnet is opposed to such flux, the impedance of the reactorwill remain high. By applying an alternating current to the winding anda currentresponsive device in series therewith, the device may be madeto operate when the reactor impedance decreases and will be inoperablewhen the reactor impedance remains high. The prior art utilized thispractice in connection with article conveyor systems wherein switchingorders, applied to articles or article-carrying containers in a conveyorsystem, were detected by reactors of the type above described. By theselective setting of magnets, a switching function throughout the systemcould be controlled and the article could be routed accordingly.

If a multi-element code is used to control the switching function therewill be required a separate reactor with its cooperating magnet for eachcode element. These reactors are generally placed in a common planetransverse to the direction of travel of the article along the conveyorsystem, and means must be provided to insure that a permanent magnetwill affect its associated reactor, but no other, including the reactorsadjacent of said associated reactor. This invention is directed to anarrangement which precludes the spurious response of a reactor to anybut its associated permanent magnet. The isolation required is achievedby positioning the reactors with their cores at right angles to thecores of their adjacent reactors.

It is a further object of the invention to provide settable permanentmagnets in the article containers of the conveyor system which willselectively cooperate with their associated reactors, depending upon theset position of such magnets.

The above-mentioned and other features and objects of this inventionwill become apparent by reference to the following description taken inconjunction with the accompanying drawings, wherein:

Fig. 1 is a schematic drawing of a portion of a con veyor system, partlyin section, showing the placement of adjacent cores and the cooperationthereof with their associated magnets;

Fig. 2 is an isometric view of a container showing the method ofmounting adjustable magnets; and

reactors are also provided with alternating current windings L1, L2,respectively. Sources of alternating current E1, B2 are seriallyconnected to the last-mentioned windings and to rectifier networks G11,G12, respectively, to theoutput of which networks are connected relaysRelI and RellI, respectively. The design of the reactors J1 and I2 issuch that the pro-magnetization windings W1, W2 are unable to saturatethe iron cores sufficiently to lower the impedance of the windings L1and L2, and consequently, insufficient alternating current passestherethrough to operate the relays RelI, RelII. In the case of reactorJ1, when the magnet M1 is brought in proximity with the core so that theflux lines indicated by the dashes aid the flux developed by-the windingW1, the impedance of the winding L1 will decrease; a voltage will beapplied to the rectifier network G11 and relay RelI will operate. Thecondenser C1 shunted across the relay tends to smooth the rectifiedalternating current derived from the network and will prevent the relayfrom chatter ing. The electrical arrangement associatedwith the reactorI2 is similar to that for the reactor J1. It will be noted however thatthe core of the reactor J2lies at right angles to the core of reactorJ1. Thus the North and South polarity of the core of J2 is as indicatedon the drawing and the magnet M2 must have its polarity at right anglesto the polarity of the magnet M1 in order to affect the core of reactorJ2. The flux path of the magnet is shown by dashed line. It will be seenthat the lines of force of a magnet which is not parallel to the lengthof its corresponding core will not affect the core and therefore notalter the impedance of the reactor. By alternately disposing the coresat right angles to each other, the cores may be placed relatively closeto each other without fear that an adjacent permanent magnet will alterits saturation.

Thus, the magnet M1 when rotated so that the North and South polarityare vertical, will affect a vertically disposed core such as J1, butwould have no efliect on a horizontally disposed core such as J2.Conversely, a horizontally disposed magnet such as M2, will affect ahorizontally situated core such as J2 but will have no effect on avertically disposed core such as II. It will also be understood that ifthe magnet M1 is rotated about the pivot D, that the flux developedthereby will oppose the flux developed by the winding W1, and no outputwill be derived from the rectifier network G11.

Similarly, if the magnet M2 is rotated 180, no output will be derivedfrom the rectifier network G12.

It will be understood that both the belt B and the bottom of the.container K must be made of diamagnetic material so that the lines offorce may pass therethrough,

It will be further understood that While only two sets of magnets andreactors are shown, it is within the scope of this invention to provideadditional magnets and reactors in order to afford additional switchingcombinations. The switching apparatus for the conveyor system may becontrolled by a series network of contacts such as shown in Fig. 1; thecontacts I and II, respectively, associated with relay Rell and RelII.

In order to maintain the magnets M1 and M2 in a fixed angular positionwith respect to the belt B, a suitable detent (not shown) may beprovided to insure the magnets will retain a quadrantal position Whilewe have described above the principles of our invention in connectionwith specific apparatus, it is to be clearly understood that thisdescription is made only by way of example and not as a limitation tothe scope of our invention as set forth in the objects thereof and inthe accompanying claims.

What is claimed is:

1. In a conveyor transport system having at least one article-carryingcontainer associated with a movable belt conveyor, the automaticcontainer routing system that comprises, a plurality of permanent magnetelements each rotatably mounted on said article-carrying container, aplurality of magnetically-responsive switching devices mounted adjacentsaid movable belt conveyor each being approximately positioned to beinfluenced principally by the magnetic field of a selected permanentmagnet element upon passage of an article-carrying containerthereacross, circuit means electrically connected to saidmagnetically-responsive switching devices for controlling said movablebelt conveyor with respect to routing of the article-carrying containerthereon, said magneticallyresponsive switching devices beingdiiferentially positioned with respect to each other to efiect maximummag- 4 netic decoupling between any single switching device and adjacentpermanent magnet elements other than the selected element for saidswitching device, said permanent magnetic elements being rotatable toselectively vary their polarity to aid or oppose the flux developed by acorresponding electromagnetic element to effect predetermined, differentswitching connections when said article-carrying container passes inmagnetic field proximity to said magnetically responsive switchingdevice.

2. The automatic container routing system as claimed in claim 1, whereinsaid magnetically-responsive switching devices comprise separateelectromagnetic elements each including a premagnetizing winding adaptedto maintain a fixed field intensity for said element and an alternatingcurrent winding of normally high impedance to current flow which iselectrically connected to a currentresp onsive control element for saidconveyor belt, each of said permanent magnet elements being adapted totrigger its associated switching device and actuate said control elementunder action of increased current flow in said alternating currentwinding induced when the flux developed by said permanent magnet elementis positioned to aid the flux developed by said pre-magnetizing winding.

3. The automatic container routing system as claimed in claim 2, whereinsaid separate electromagnetic elements are positioned in substantiallylinear alignment transverse to the direction of movement of saidconveyor belt.

4. The automatic container routing system as claimed in claim 3, whereinsaid permanent magnet elements are mounted in linear alignment on saidarticle-carrying container with each element in substantially verticalalignment with a corresponding electromagnetic element.

References Cited in the file of this patent .h. Wm,

